Conventional communications satellites, such as transponding satellites, which utilize a non-linear power amplifier in the transmitter, operate that amplifier at or near saturation where the non-linear power amplifier is most efficient. Using power control with such a non-linear amplifier results in an unacceptable loss in efficiency. To overcome this, such communications satellites generally use linearized traveling wave tube amplifiers (TWTAs). To assure adequate reception of the downlinked signals from the satellite, the TWTAs generally have the same power levels, and the satellites generally provide the same power to each TWTA. However, uniform power levels are not necessarily needed for all of the downlink beams.
Further, the TWTAs are frequently oversized to compensate for attenuation, for example due to rain or other inclement conditions. The power is then reduced when there is no rain or other attenuation-causing condition. The satellites generally get their power from solar cells or other sources carried on the satellite. Making excess power available thus requires excess solar cells, which results in increased weight on the satellite. This not only is costly in providing the additional solar cells, but also costly by making launching of the satellite into orbit more expensive.